PHOTO

This species is described as having a white body, including white tentacular anterior foot corners and white dorso-lateral processes. The oral tentacles have a white base but are primarily orange, the gills are white with orange edging on the dorsal side, and the rhinophores clubs are similarly white with orange at the tip and down the dorsal surface. The posterior tip of the foot is described as having "an occasional orange pigment spot". The largest animals examined by Gosliner & Fahey were 5 mm long alive.

Gosliner & Fahey describe the radular morphology of T. vitta as closely resembling that of T. aurata Rudman, 1987 from Hong Kong "but the outermost denticle of T. aurata is longer with a base that extends the entire width of the tooth ". I don't know what they mean by that, as when I compare SEM photos of T. aurata from both Hong Kong [message #21436] and New Caledonia [message #21437 ] I can see no real difference.

Some animals previously identified on the Forum as T. cf aurata [message #313] and some identified as T. aurata [#17725, #1569] appear to match the colour pattern of T. vitta. See Trapania cf. aurata for animals with slightly different colour pattern, which may or may not be variants of this species. See also discussion [#21438 ] concerning the similarly coloured T. aurata, and message #9599 concerning Trapania sp. 8.

I'm glad to see the Trapania story is continuing to grow. Your animal certainly looks like T. vitta, but the point I have been trying to make is that it is not a good idea to be too 'sure' in identifying some of these species. To say "This is in fact T. vitta" suggest there is some book or supreme database with all the correct answers - but there isn't. I don't know if the intermediate colour patterns mean there is one variable species, two species with overlapping colour patterns or perhaps three or four species. Personally I would find the existence of a 'big book' with all the answers rather depressing. I prefer being able to stumble around discovering new bits of information -some small, some larger - but all very exciting

Dear Erwin
This is another message from a few years ago. As I discuss separately [message #21438] I have some difficulty distinguishing T. aurata and T. vitta. The absence of orange on the extra-rhinophoral and extra-branchial processes seems to fit the description of T. vitta, but if there are two species, then the general body shape and relatively fine orange markings on the rhinophores and gills would suggest T. aurata.

In my earlier discussion I should have mentioned Trapania sp. 8. Is it just another colour form of one species? It has orange rhinophores, oral tentacles, tentacular foot corners, extra-rhinophoral and extra-branchial processes and a large orange line on the posterior tip of the foot. The gills are white. The orange on the extra-rhinophoral and extra-branchial processes differs from what we see in T. aurata in that the orange pigment covers the whole of the process, not just a dorsal line.

September 4, 2006
From: Brian Francisco

Note added 12 March 2008: This is probably the species which has recently been named Trapania vitta as it lacks orange on the dorso-lateral processes but differs in having orange on anterior foot corners.

Dear Brian,
Yes this is T. aurata. One interesting thing is that it is on this dysideid sponge. As you will see if you look a the other species of Trapania on the Forum is that they are often found on similar sponges. In my earlier message on this species [#3774] - where I mistakenly identify the sponge as an aplysillid - I mention the little whitish blobs on stalks which are probably the entoproct food of the nudibranch. If you look carefully at your photos you will see small out of focus white blobs which are most likely the same thing. It seems all species of Trapania feed on entoprocts living on these sponges.

Dear Vinka,This is Trapania aurata. A puzzling feature of species of Trapania is we don't know what they eat. Sometimes they are found in quite large numbers, usually on a sponge which would suggest they are sponge-feeders. However the shape of their radular teeth is quite unlike that of any other group of sponge feeders, and they are related to animals which feed on bryozoans.

This mystery is quite similar to the mystery surrounding the food of species of the Gastropteridae (Sagaminopteron, Siphopteron, Gastropteron). The are also commonly found on sponges but have radular teeth similar in shape to the related philinoid bubble-shells such as Philine.

Dear Mike,Thanks for the picture. I'm sorry you didn't collect some specimens as I have my doubts whether they are the same. Its not just that the Bali specimens are more reddish orange than yellow, but they lack any colour on their lateral processes.

Neville Coleman's illustrated specimens are probably the same as yours with no sign of colour on the lateral processes.